The present invention relates to methods and compositions for the treatment and diagnosis of immune disorders, especially T lymphocyte-related disorders, including, but not limited to, chronic inflammatory diseases and disorders, such as Crohn""s disease, reactive arthritis, including Lyme disease, insulin-dependent diabetes, organ-specific autoimmunity, including multiple sclerosis, Hashimoto""s thyroiditis and Grave""s disease, contact dermatitis, psoriasis, graft rejection, graft versus host disease, sarcoidosis, atopic conditions, such as asthma and allergy, including allergic rhinitis, gastrointestinal allergies, including food allergies, eosinophilia, conjunctivitis, glomerular nephritis, certain pathogen susceptibilities such as helminthic (e.g., leishmaniasis) and certain viral infections, including HIV, and bacterial infections, including tuberculosis and lepromatous leprosy. For example, genes which are differentially expressed within and among T helper (TH) cells and TH cell subpopulations, which include, but are not limited to TH0, TH1 and TH2 cell subpopulations are identified. Genes are also identified via the ability of their gene products to interact with gene products involved in the differentiation, maintenance and effector function of such TH cells and TH cell subpopulations. The genes identified can be used diagnostically or as targets for therapeutic intervention. In this regard, the present invention provides methods for the identification and therapeutic use of compounds as treatments of immune disorders, especially TH cell subpopulation-related disorders. Additionally, methods are provided for the diagnostic evaluation and prognosis of TH cell subpopulation-related disorders, for the identification of subjects exhibiting a predisposition to such conditions, for monitoring patients undergoing clinical evaluation for the treatment of such disorders, and for monitoring the efficacy of compounds used in clinical trials.
Two distinct types of T lymphocytes are recognized: CD8+ cytotoxic T lymphocytes (CTLs) and CD4+ helper T lymphocytes (TH cells). CTLs recognize and kill cells which display foreign antigens of their surfaces. CTL precursors display T cell receptors that recognize processed peptides derived from foreign proteins, in conjunction with class I MHC molecules, on other cell surfaces. This recognition process triggers the activation, maturation and proliferation of the precursor CTLs, resulting in CTL clones capable of destroying the cells exhibiting the antigens recognized as foreign.
TH cells are involved in both humoral and cell-mediated forms of effector immune responses. With respect to the humoral, or antibody, immune response, antibodies are produced by B lymphocytes through interactions with TH cells. Specifically, extracellular antigens are endocytosed by antigen-presenting cells (APCs), processed, and presented preferentially in association with class II major histocompatibility complex (MHC) molecules to CD4+ class II MHC-restricted TH cells. These TH cells in turn activate B lymphocytes, resulting in antibody production.
The cell-mediated, or cellular, immune response, functions to neutralize microbes which inhabit intracellular locations. Foreign antigens, such as, for example, viral antigens, are synthesized within infected cells and presented on the surfaces of such cells in association with class I MHC molecules. This, then, leads to the stimulation of the CD8+ class I MHC-restricted CTLs.
Some agents, such as mycobacteria, which cause tuberculosis and leprosy, are engulfed by macrophages and processed in vacuoles containing proteolytic enzymes and other toxic substances. While these macrophage components are capable of killing and digesting most microbes, agents such as mycobacteria survive and multiply. The agents, antigens are processed, though, by the macrophages and presented preferentially in association with class II MHC molecules to CD4+ class II MHC-restricted TH cells, which become stimulated to secrete interferon-xcex3, which, in turn, activates macrophages. Such activation results in the cells"" exhibiting increased bacteriocidal ability.
TH cells are composed of at least two distinct subpopulations, termed TH1 and TH2 cell subpopulations. Evidence suggests that TH1 and TH2 subtypes represent extremely polarized populations of TH cells. While such subpopulations were originally discovered in murine systems (reviewed in Mosmann, T. R. and Coffman, R. L., 1989, Ann. Rev. Immunol. 7:145), the existence of TH1- and TH2-like subpopulations has also been established in humans (Del Prete, A. F. et al., 1991, J. Clin. Invest. 88:346; Wiernenga, E. A. et al., 1990, J. Imm. 144:4651; Yamamura, M. et al., 1991, Science 254:277; Robinson, D. et al., 1993, J. Allergy Clin. Imm. 92:313). While TH1-like and TH2-like cells can represent the most extremely polarized TH cell subpopulations, other TH cell subpopulations, such as TH0 cells (Firestein, G. S. et al., 1989, J. Imm. 143:518), which represent TH cells which have characteristics of TH1 and TH2 cell subpopulations.
TH1-like and TH2-like cells appear to function as part of the different effector functions of the immune system (Mosmann, T. R. and Coffmann, R. L., 1989, Ann. Rev. Imm. 7:145). Specifically, TH1-like cells direct the development of cell-mediated immunity, triggering phagocyte-mediated host defenses, and are associated with delayed hypersensitivity. Accordingly, infections with intracellular microbes tend to induce TH1-type responses. TH2 cells drive humoral immune responses, which are associated with, for example, defenses against certain helminthic parasites, and are involved in antibody and allergic responses.
It has been noted that the ability of the different TH cell types to drive different immune effector responses is due to the exclusive combinations of cytokines which are expressed within a particular TH cell subpopulation. For example, TH1 cells are known to secrete interleukin-2 (IL-2), interferon-xcex3 (IFN-xcex3), and lymphotoxin, while TH2 cells secrete interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-10 (IL-10).
It is thought that TH1 and TH2 subpopulations arise from a common naive precursor (referred to as THP). For example, naive CD4+ cells from mice which express a single transgenic T cell receptor can be induced to develop into either the TH1 or TH2 cell type. The conditions of antigen stimulation, including the nature and amount of antigen involved, the type of antigen-presenting cells, and the type of hormone and cytokine molecules present seem to all represent determinants of the pattern of TH1 versus TH2 differentiation, with, perhaps, the decisive role belonging to the cytokines present. With such a complex series of possible determinants, a full accounting of the exact factors important in driving TH1 or TH2 differentiation are, as yet largely unknown.
Further, it has recently been noted that, in addition to CD4+ TH cells, CD8+ CTLs can, under certain conditions, also exhibit TH1-like or TH2-like cytokine profiles (Seder, R. A. et al., 1995, J. Exp. Med. 181:5-7; Manetti, R. et al., 1994, J. Exp. Med. 180:2407-2411; Maggi, E. et al., 1994, J. Exp. Med. 180:489-495). While the precise functional role of such CD8+ TH-like cells is currently unknown, these cell subpopulations appear to have great relevance to immune responses against infectious agents such as viruses and intracellular parasites.
Once TH1 and TH2 subpopulations are expanded, the cell types tend to negatively regulate one another through the actions of cytokines unique to each. For example, TH1-produced IFN-xcex3 negatively regulates TH2 cells, while TH2-produced IL-10 negatively regulates TH1 cells. Moreover, cytokines produced by TH1 and TH2 antagonize the effector functions of one another (Mosmann, T. R. and Moore, 1991, Immunol. Today 12:49).
Failure to control or resolve an infectious process often results from an inappropriate, rather than an insufficient immune response, and can underlie a variety of distinct immunological disorders. Such disorders can include, for example, atopic conditions (i.e., IgE-mediated allergic conditions) such as asthma, allergy, including allergic rhinitis, dermatitis, including psoriasis, pathogen susceptibilities, chronic inflammatory disease, organ-specific autoimmunity, graft rejection and graft versus host disease. For example, nonhealing forms of human and murine leishmaniasis result from strong but counterproductive TH2-like-dominated immune responses. Lepromatous leprosy also appears to feature a prevalent, but inappropriate, TH2-like response.
It is possible that another example can be HIV infection. Here, it has been suggested that a drop in the ratio of TH1-like cells to other TH cell subpopulations can play a critical role in the progression toward disease symptoms. Further, it has been noted that, at least in vitro, TH2-like clones appear to be more efficient supporters of HIV viral replication than TH1-like clones.
Further, while TH1-mediated inflammatory responses to many pathogenic microorganisms are beneficial, such responses to self antigens are usually deleterious. It has been suggested that the preferential activation of TH1-like responses is central to the pathogenesis of such human inflammatory autoimmune diseases as multiple sclerosis and insulin-dependent diabetes. For example, TH1-type cytokines predominate in the cerebrospinal fluid of patients with multiple sclerosis, pancreases of insulin-dependent diabetes patients, thyroid glands of Hashimoto""s thyroiditis, and gut of Crohn""s disease patients, suggesting that such patients mount a TH1-like, not a TH2-like, response to the antigen(s) involved in the etiopathogenesis of such disorders.
A primary goal, for both diagnostic and therapeutic reasons, therefore, would be the ability to identify, isolate and/or target members of a particular TH cell subpopulation. The ability to identify those genes which are differentially expressed within and/or among such TH cell subpopulations is required to achieve such a goal. To date, investigations have focused on the expression of a limited number of specific known cytokines and cytokine receptors in the TH cell population. Cytokines, however, exert effects on cell types in addition to specific TH cell subpopulations, i.e., exhibit a variety of pleiotropic effects. It would be beneficial, therefore, to identify reliable markers (e.g., gene sequences) of TH cell subpopulations whose effects are TH cell subpopulation specific, e.g., which, unlike secreted cytokines, are TH cell subpopulation specific.
The present invention relates to methods and compositions for the treatment of immune disorders, especially T helper (TH) cell and TH cell-like related disorders. First, genes are identified and described which are differentially expressed within and among TH cells and TH cell subpopulations. Second, genes are identified and described which are differentially expressed within TH cell subpopulations in TH cell subpopulation-related disorders. The modulation of the expression of the identified genes and/or the activity of the identified gene products can be utilized therapeutically to ameliorate immune disorder symptoms and to modulate TH cell responsiveness, for example, responsiveness to antigen. Further, the identified genes and/or gene products can be used to diagnose individuals exhibiting or predisposed to such immune disorders. Still further, the identified genes and/or gene products can be used to detect TH cell responsiveness, for example, responsiveness to antigen.
xe2x80x9cDifferential expression,xe2x80x9d as used herein, refers to both quantitative as well as qualitative differences in the genes"" temporal and/or cellular expression patterns within and among the TH cell subpopulations. Differentially expressed genes can represent xe2x80x9cfingerprint genesxe2x80x9d and/or xe2x80x9ctarget genesxe2x80x9d.
xe2x80x9cFingerprint gene,xe2x80x9d as used herein, refers to a differentially expressed gene whose expression pattern can be utilized as part of a prognostic or diagnostic evaluation of immune disorders, e.g., TH cell-related disorders, or which, alternatively, can be used in methods for identifying compounds useful in the treatment of such disorders. For example, the effect of the compound on the fingerprint gene expression normally displayed in connection with the disorder can be used to evaluate the efficacy of the compound as a treatment for such a disorder, or may, additionally, be used to monitor patients undergoing clinical evaluation for the treatment of such disorders.
xe2x80x9cFingerprint pattern,xe2x80x9d as used herein, refers to the pattern generated when the expression pattern of a series (which can range from two up to all the fingerprint genes which exist for a given state) of fingerprint genes is determined. A fingerprint pattern can be used in the same diagnostic, prognostic, and compound identification methods as the expression of a single fingerprint gene.
xe2x80x9cTarget gene,xe2x80x9d as used herein, refers to a differentially expressed gene involved in immune disorders, e.g., TH cell related disorders, such that modulation of the level of target gene expression or of a target gene product activity can act to ameliorate the immune disorder. Compounds that modulate target gene expression or activity of the target gene product can be used in the treatment of immune disorders.
Further, xe2x80x9cpathway genesxe2x80x9d are defined via the ability of their gene products to interact with gene products involved in TH cell subpopulation-related disorders and/or to interact with gene products which are involved in the differentiation and effector function of the TH cell subpopulations. Pathway genes can also exhibit target gene and/or fingerprint gene characteristics.
Although the target, fingerprint and/or pathway genes described herein can be differentially expressed within and/or among TH cell subpopulations, and/or can interact with TH cell subpopulation gene products, the genes can also be involved in mechanisms important to additional immune processes.
The invention encompasses the following nucleotides, host cells expressing such nucleotides and the expression products of such nucleotides: (a) nucleotides that encode a mammalian differentially expressed and/or pathway gene product including, but not limited to a human and murine 10, 54, 57, 105, 106, 161 and 200 gene product; (b) nucleotides that encode portions of a differentially expressed and/or pathway gene product that corresponds to its functional domains, and the polypeptide products encoded by such nucleotide sequences, and in which, in the case of receptor-type gene products, such domains include, but are not limited to extracellular domains (ECD), transmembrane domains (TM) and cytoplasmic domains (CD); (c) nucleotides that encode mutants of a differentially expressed and/or pathway gene product, in which all or part of one of its domains is deleted or altered, and which, in the case of receptor-type gene products, such mutants include, but are not limited to, soluble receptors in which all or a portion of the TM is deleted, and nonfunctional receptors in which all or a portion of CD is deleted; and (d) nucleotides that encode fusion proteins containing a differentially expressed and/or pathway gene product or one of its domains fused to another polypeptide.
The present invention also includes the products of such fingerprint, target, and pathway genes, as well as antibodies to such gene products. Furthermore, the engineering and use of cell- and animal-based models of TH cell subpopulation-related disorders to which such gene products can contribute, are also described.
The present invention also relates to methods for prognostic and diagnostic evaluation of various TH cell subpopulation-related disorders, and for the identification of subjects who are predisposed to such disorders. Furthermore, the invention provides methods for evaluating the efficacy of drugs for immune disorders, and monitoring the progress of patients involved in clinical trials for the treatment of such disorders.
The TH cell subpopulation-related disorders described herein can include, for example, TH1 or TH1-like related disorders or can, alternatively, include TH2 or TH2-like related disorders. Examples of TH1 or TH1-like related disorders include chronic inflammatory diseases and disorders, such as Crohn""s disease, reactive arthritis, including Lyme disease, insulin-dependent diabetes, organ-specific autoimmunity, including multiple sclerosis, Hashimoto""s thyroiditis and Grave""s disease, contact dermatitis, psoriasis, graft rejection, graft versus host disease and sarcoidosis. Examples of TH2 or TH2-like related disorders include atopic conditions, such as asthma and allergy, including allergic rhinitis, gastrointestinal allergies, including food allergies, eosinophilia, conjunctivitis, glomerular nephritis, certain pathogen susceptibilities such as helminthic (e.g., leishmaniasis) and certain viral infections, including HIV, and bacterial infections, including tuberculosis and lepromatous leprosy.
It is further contemplated that the methods and compositions described herein can be utilized in the prognostic and diagnostic evaluation of disorders involving other immune cells, including CD8+ CTLs, exhibiting TH-like cell subpopulation gene expression patterns and/or activity. It is still further contemplated that the methods and compositions described herein can be utilized in the amelioration of symptoms stemming from disorders involving such immune cells, especially such CD8+ CTLs, which exhibit TH-like cell subpopulation gene expression patterns and/or activity.
The invention further provides methods for the identification of compounds which modulate the expression of genes or the activity of gene products involved in TH cell subpopulation-related disorders and processes relevant to the differentiation, maintenance and/or effector function of the subpopulations. Still further, the present invention provides methods for the treatment of TH cell subpopulation-related disorders which can, for example, involve the administration of such modulatory compounds to individuals exhibiting TH cell subpopulation-related disorder symptoms or tendencies. Additionally, treatment can result in the stimulation or depletion of one or more of the TH cell subpopulations.
xe2x80x9cStimulationxe2x80x9d, as used herein, can refer to an effective increase in the number of cells belonging to a TH cell subpopulation, via, for example, the proliferation of such TH cell subpopulation cells. The term can also refer to an increase in the activity of cells belonging to a TH cell subpopulation, as would be evidenced, for example, by a per cell increase in the expression of the TH cell subpopulation-specific cytokine pattern.
xe2x80x9cDepletionxe2x80x9d, as used herein, can refer to an effective reduction in the number of cells belonging to a TH cell subpopulation, via, for example, a reduction in the proliferation of such TH cell subpopulation cells. The term can also refer to a decrease in the activity of cells belonging to a TH cell subpopulation, as would be evidenced, for example, by a per cell decrease in the expression of the TH cell subpopulation-specific cytokine pattern.
The invention is based, in part on systematic search strategies involving paradigms which utilize TH0, TH1, TH2, TH1-like and TH2-like cells, in systems which mimic the activity of the immune system or immune disorders, coupled with sensitive and high-throughput gene expression assays, to identify genes differentially expressed within and/or among TH cell subpopulations. In contrast to approaches that merely evaluate the expression of a single known gene product presumed to play a role in some immune cell-related process or disorder, the search strategies and assays used herein permit the identification of all genes, whether known or novel, which are differentially expressed within and among TH cell subpopulations, as well as making possible the characterization of their temporal regulation and function in the TH cell response and/or in TH cell mediated disorders. This comprehensive approach and evaluation permits the discovery of novel genes and gene products, as well as the identification of a constellation of genes and gene products (whether novel or known) involved in novel pathways (e.g., modulation pathways) that play a major role in the TH-cell mediated immune responses and TH cell subpopulation-related disorders. Thus, the present invention makes possible the identification and characterization of targets useful for prognosis, diagnosis, monitoring, rational drug design, and/or therapeutic intervention of immune system disorders.
The Examples described in Sections 6 through 8, below, demonstrate the successful use of the search strategies of the invention to identify genes which are differentially expressed among and/or within TH cell subpopulations. Section 9 describes the successful cloning of a human homolog of one of the identified genes (the 200 gene).
The 102 and 103 genes represent genes which, while previously known, are shown here to be differentially expressed among TH cell subpopulations. Specifically, the 102 gene corresponds to the Granzyme A, or Hanukah factor, gene, which encodes a trypsin-like serine protease. While this gene had previously been reported to be expressed in natural killer cells and a fraction of CD4+ cells, the results described herein reveal, for the first time, that the gene is differentially expressed within the TH2 cell subpopulation. Specifically, the 102 gene is expressed at a level many-fold higher in the TH2 cell subpopulation than in the TH1 cell subpopulation.
The 103 gene corresponds to a gene known as the T1, ST-2 or Fit-1 gene, which encodes, possibly via alternative splicing, both transmembrane and soluble gene products. The gene 103 products belong to the immunoglobulin superfamily, and bear a high resemblance to the interleukin-1 (IL-1) receptor. The results presented herein demonstrate, for the first time, that this gene is expressed, in vivo, in a tightly controlled TH2-specific fashion. Thus, given its status as both a TH2 cell subpopulation-specific marker and a cell surface protein, the gene 103 products can be utilized in a variety of methods to diagnose and/or modulate immune system disorders, in particular TH2 cell subpopulation-related disorders.
In addition to these known genes, the systematic search strategies described herein were used to identify several novel genes which are differentially expressed within and/or among TH cell subpopulations. Specifically, these include the 10, 54, 57, 105, 106, 161 and 200 genes.
The 54, 105, 106 and murine 200 genes are each shown to be differentially expressed within the TH1 cell subpopulation. Specifically, these genes are expressed at levels many-fold higher in TH1 cell subpopulations than in TH2 cell subpopulations.
The novel 54 gene product is a 371 amino acid cysteine protease, as evidenced by the presence of three thiol protease domains at approximately amino acid residue 145 to 156 (CYS domain), approximately amino acid residue 287 to 297 (HIS domain) and approximately amino acid residue 321 to 340 (ASN domain) of the 54 gene product amino acid sequence.
The 10 and 57 genes represent TH inducible gene sequences. That is, the expression of such genes in unstimulated TH cells is either undetectable or barely detectable, but is significantly upregulated in both stimulated TH1 and stimulated TH2 cells. Thus, the 10 and 57 genes and/or their gene products can represent new targets for therapeutic treatment as part of a non-TH cell subpopulation dependent intervention program.
The 10 gene product is a 338 amino acid receptor molecule which is a particularly suitable target for such a program in that the 10 gene product belongs to a class of proteins having a seven transmembrane domain sequence motif, which tend to represent G protein-coupled receptor molecules. The 10 gene product structure, therefore, indicates that it may be involved in signal transduction events which may be important to T cell responses in general, and further indicates that modulation of 10 gene product may effectively ameliorate a wide range of T cell-related disorders.
Specifically, because the 10 gene product is a transmembrane product, its activity, via either a physical change in the number of 10 gene-expressing cells or by a change in the functional level of 10 gene product activity, can be particularly amenable to modulation. For example, natural ligands, derivatives of natural ligands and antibodies which bind to the 10 gene product can be utilized to reduce the number of induced T cells present by either physically separating such-cells away from other cells in a population, or, alternatively, by targeting the specific destruction of the induced T cells or inhibiting the proliferation of such T cells.
Additionally, compounds such as 10 gene sequences or gene products such as, for example, soluble 10 gene products, can be utilized to reduce the level of induced T cell activity, and, ultimately, bring about the amelioration of a wide range of T cell-related disorders. For example, in the case of soluble gene 10 gene products, the compounds can compete with the endogenous (i.e., natural) ligand for the 10 gene product, leading to a modulation of induced T cell activity. Soluble proteins or peptides, such as peptides comprising one or more of the extracellular domains, or portions and/or analogs thereof, of the 10 gene product, including, for example, soluble fusion proteins such as Ig-tailed fusion proteins, can be particularly useful for this purpose. Additionally, antibodies directed against one or more of the extracellular portions of the 10 gene product may either reduce 10 gene product function by, for example, blocking ligand binding. Additionally, antibodies directed against the 10 gene product can, in certain instances, serve to increase the level of 10 gene product activity.
The receptor nature of the 10 gene product makes possible useful methods for the identification of compounds which modulate the receptor""s functional activity and which can act as therapeutic agents in the amelioration of a wide range of T cell-related disorders. For example, functional assays which measure intracellular calcium release levels may be utilized to identify compounds which act as either agonists or antagonists of 10 gene product activity. Such assays may, additionally, be utilized to identify the natural 10 gene product ligand. Still further, any of these modulatory compounds can be utilized as therapeutic agents for the amelioration of a wide range of T cell-related disorders.
Finally, the 161 gene is shown to be an additional new and potentially interesting target for a therapeutic method aimed at the amelioration of immune disorder related symptoms. In fact, it is possible that 161 gene expression may be indicative of the presence of yet another TH cell subpopulation, in addition to TH1, TH2 and TH0 cell subpopulations.
The identification of TH cell subpopulation specific markers can be utilized in the treatment of a number of immune disorders, especially TH cell subpopulation-related disorders. For example, markers for the TH2 subpopulation can be used to ameliorate conditions involving an inappropriate IgE immune response, including but not limited to the symptoms which accompany atopic conditions such as allergy and/or asthma. IgE-type antibodies are produced by stimulated B cells which require, at least in part, IL-4 produced by the TH2 cell subpopulation. Therefore, a treatment which reduces the effective concentration of secreted IL-4, e.g., by reducing the activity or number of TH2 cells, will bring about a reduction in the level of circulating IgE, leading, in turn, to the amelioration or elimination of atopic conditions. Any of the TH2-specific gene products described herein can, therefore, be used as a target to reduce or deplete the number and/or activity of TH2 cell subpopulation cells for the treatment of such conditions.
The 103 gene can be particularly suitable for this purpose since one of its gene products is a membrane-bound TH2 cell subpopulation molecule. Accordingly, natural ligands, derivatives of natural ligands and antibodies which bind to this 103 gene product, can be utilized to reduce the number of TH2 cells present by either physically separating such cells away from other cells in a population, or, alternatively, by targeting the specific destruction of TH2 cells or inhibiting the proliferation of such TH2 cells. Additionally, compounds such as 103 gene sequences or gene products can be utilized to reduce the level of TH2 cell activity, cause a reduction in IL-4 production, and, ultimately, bring about the amelioration of IgE related disorders. For example, the-compounds can compete with the endogenous (i.e., natural) ligand for the 103 gene product. The resulting reduction in the amount of ligand-bound 103 gene transmembrane protein will modulate TH2 cellular activity. Soluble proteins or peptides, such as peptides comprising the extracellular domain, or portions and/or analogs thereof, of the 103 gene product, including, for example, soluble fusion proteins such as Ig-tailed fusion proteins, can be particularly useful for this purpose.
The identification of TH cell subpopulation specific markers can additionally be utilized in the treatment of a TH1 cell subpopulation-related disorders. For example, markers for the TH1 cell subpopulation can be used to ameliorate conditions involving an inappropriate cell-mediated immune response, including, but not limited to chronic inflammatory and autoimmune disorders. Further, transgenic animals overexpressing or misexpressing such gene sequences and/or transgenic xe2x80x9cknockoutxe2x80x9d animals exhibiting little or no expression of such sequences can be utilized as animal models for TH cell subpopulation-related disorders. The Example presented in Section 11, below, describes the production of 200 and 103 transgenic animals.
TH1 cell subpopulation specific gene sequences and/or gene products such as the 54 (which encodes a 371 amino acid cysteine protease gene product), 105, 106 and 200 (the murine homolog of which encodes a 280 amino acid transmembrane gene product, the human homolog of which encodes a 301 amino acid transmembrane gene product, both of which are members of the Ig superfamily) genes can, therefore, be suitable for ameliorating such TH1 cell subpopulation-related disorders. The 200 gene product can be particularly suitable for such a purpose in that it is not only TH1 cell subpopulation-restricted, but the Ig superfamily 200 gene product is, additionally, membrane-bound. Therefore, natural ligands, derivatives of natural ligands and antibodies which bind to the 200 gene product can be utilized to reduce the number of TH1 cells present by either physically separating such cells away from other cells in a population, or, alternatively, by targeting the specific destruction of TH1 cells or inhibiting the proliferation of such TH1 cells. Additionally, compounds such as 200 gene sequences or gene products such as soluble 200 gene products, can be utilized to reduce the level of TH2 cell activity, thus bringing about the amelioration of TH1 cell subpopulation-related disorders. For example, the compounds can compete with the endogenous (i.e., natural) ligand for the 200 gene product. The resulting reduction in the amount of ligand-bound 200 gene transmembrane protein will modulate TH2 cellular activity. Soluble proteins or peptides, such as peptides comprising the extracellular domain, or portions (such as, for example, the Ig portion) and/or analogs thereof, of the 200 gene product, including, for example, soluble fusion proteins such as Ig-tailed fusion proteins, can be particularly useful for this purpose. The Example presented in Section 10, below, describes the construction and expression of 200 gene product and 103 gene product Ig fusion constructs and proteins.
The term xe2x80x9cTH cell subpopulationxe2x80x9d, as used herein, refers to a population of TH cells exhibiting a gene expression pattern (e.g., a discrete pattern of cytokines and/or receptor or other cell surface molecules) and activity which are distinct from the expression pattern and activity of other TH cells. Such TH cell subpopulations can include, but are not limited to, TH0, TH1 and TH2 subpopulations, which will, for clarity and example, and not by way of limitation, be frequently used herein as representative TH cell subpopulations.
The term xe2x80x9cTH-like cell subpopulationxe2x80x9d (e.g., xe2x80x9cTH1-likexe2x80x9d or xe2x80x9cTH2-likexe2x80x9d), as used herein is intended to refer not only to a population of CD4+ TH cells having the properties described, above, for a TH cell subpopulation, but also refers to CD4xe2x88x92 cells, including CD8+ CTLs, which exhibit TH-like cytokine expression patterns.
xe2x80x9cDifferential expressionxe2x80x9d, as used herein, refers to both quantitative as well as qualitative differences in the genes"" temporal and/or cellular expression patterns.
xe2x80x9cTarget genexe2x80x9d, as used herein, refers to a differentially expressed gene involved in immune disorders and/or in the differentiation, maintenance and/or effector function of TH cell subpopulations, such that modulation of the level of target gene expression or of target gene product presence and/or activity can, for example, act to result in the specific depletion or repression, or, alternatively, the stimulation or augmentation of one or more TH cell subpopulation, bringing about, in turn, the amelioration of symptoms of immune disorders, e.g., TH cell subpopulation-related disorders. A target gene can also exhibit fingerprint and/or pathway gene characteristics.
xe2x80x9cFingerprint gene,xe2x80x9d as used herein, refers to a differentially expressed gene whose mRNA expression pattern, protein level and/or activity can be utilized as part of a prognostic or diagnostic in the evaluation of immune disorders, e.g., TH cell subpopulation-related disorders, or which, alternatively, can be used in methods for identifying compounds useful for the treatment of such disorders, by, for example, evaluating the effect of the compound on the fingerprint gene expression normally displayed in connection with the disease. A fingerprint gene can also exhibit target and/or pathway gene characteristics.
xe2x80x9cFingerprint pattern,xe2x80x9d as used herein, refers to the pattern generated when the mRNA expression pattern, protein level and/or activity of a series (which can range from two up to all the fingerprint genes which exist for a given state) of fingerprint genes is determined. A fingerprint pattern can be a part-of the same methods described, above, for the expression of a single fingerprint gene.
xe2x80x9cPathway genesxe2x80x9d, as used herein, refers to a gene whose product exhibits an ability to interact with gene products involved in immune disorders, e.g., TH cell subpopulation-related disorders and/or to interact with gene products which are involved in the differentiation and effector function of TH cell subpopulations. Pathway genes can also exhibit target gene and/or fingerprint gene characteristics.
xe2x80x9cNegative modulationxe2x80x9d, as used herein, refers to a reduction in the level and/or activity of target gene product relative to the level and/or activity of the target gene product in the absence of the modulatory treatment. Alternatively, the term, as used herein, refers to a reduction in the number and/or activity of cells belonging to the TH cell subpopulation relative to the number and/or activity of the TH cell subpopulation in the absence of the modulatory treatment.
xe2x80x9cPositive modulationxe2x80x9d, as used herein, refers to an increase in the level and/or activity of target gene product relative to the level and/or activity of the gene product in the absence of the modulatory treatment. Alternatively, the term, as used herein, refers to an increase in the number and/or activity of cells belonging to the TH cell subpopulation, relative to the number and/or activity of the TH cell subpopulation in the absence of the modulatory treatment.